(1) Field of the Invention
This invention relates to shoe machines, and more particularly to an air blast mechanism and a safety mechanism to prevent hot cement from being undesirably ejected from an insole nozzle.
(2) Prior Art
The dispensing of hot thermoplastic adhesive, or cement in a controlled manner is necessary for safe, efficient, injury free shoe manufacture. The cement is discharged generally through a U-shaped nozzle arrangement disposed about the periphery of an insole support plate on a shoe lasting machine. The nozzle has an array of orifii that permits the ejecting of the hot cement onto the bottom surface of an insole held thereadjacent. The nozzles may eject cement onto flat lasted shoe bottoms onto welt-type shoe bottoms, or high heel shoes, depending upon the type of shoe being lasted. Problems arise when the cement is inadvertently sprayed onto the upper which is to be lasted to the insole, or when any cement fails to reach the portion of the insole heelward of the ball break in a toe and ball lasting operation. Of greater concern is the possibility of hot cement being sprayed on a lasting machine operator when a shoe is not disposed on the insole support plate, and when the operative mechanism which causes the cement ejection from the nozzle is accidentally activated. Neither of the above concerns appear to be considered by the prior art, however, certain shoe machine mechanisms may be exemplified as in the nozzle art by U.S. Pat. Nos. 3,943,885; 3,570,454; 3,906,569; and 3,422,797. Prior art which embody devices for melting and/or dispensing molten cement as shown in U.S. Pat. Nos. 3,239,103 and 3,318,481.
It is an object of the present invention, to provide a shoe lasting machine with a cement dispensing apparatus that can be controlled to prevent unintentional hot cement ejection when there is no shoe to be lasted on the machine.
It is a further object of the present invention to provide a nozzle that will prevent cement from being inadvertently sprayed on the inside of the uppers prior to lasting thereof.
It is yet another object of the present invention to provide a nozzle that will permit the ejection of cement to portions of an insole that are not in very close contact with the nozzle.